Okay, it’s a really good cutter. Actually, it’s pretty much unhittable. It averages 93, and gets up to 97. Here is Jansen’s line from the three games he appeared in during the NLDS: 2.1 IP, 1 H, 1 BB, 7 K

According to BrooksBaseball, Jansen threw 43 pitches in his three outings, 40 of them being cutters. 12 cutters were taken for balls, 11 were fouled off, nine were called strikes, and eight were swung on and missed. One was put into play, a bloop single off the bat of Andrelton Simmons.

Kenley Jansen, a native of Willemstad, Curacao, was signed by the Dodgers as a catcher back in 2005. Not surprisingly, he possessed a cannon arm. However, he couldn’t hit, and after posting a .198/.256/.276 line in 2009, the Dodgers began the process of moving his arm to the mound.

It didn’t take Jansen long to reach the major leagues, and since 2010, he has held hitters to a .158/.245/.249 line, with a 39.8% strikeout rate that only Craig Kimbrel and Aroldis Chapman can top.

Since 2012, Jansen has been throwing the cutter as frequently as Mariano Rivera. According to Fangraphs, the cutter has been worth 40 runs above average in that time. The next closest cutter-thrower is Chicago Cubs pitcher Travis Wood at 24 runs above average. Ordinarily, I would throw in a caveat about how pitches exist in the context of repertoires, but Jansen’s repertoire is 87 percent cutters.

That contrast alone, while impressive, doesn’t do Kenley Jansen and his nasty cutter justice. While hitters know the cutter is coming, it has a 15.2 percent whiff rate, roughly the same as Chapman’s fastball. Wood’s cutter has a 7.0 percent whiff rate. Rivera’s cutter has a 10.3 percent whiff rate.

When hitters do manage to make contact off Jansen’s cutter, they haven’t done much, as shown by their .261 BABIP against the cutter.

Mariano Rivera and his cutter finally decided to hang it up, after 19 seasons of unparalleled dominance. There are some similarities. Both were originally position players, Rivera a shortstop, and Jansen a catcher. They each spent a couple seasons in a setup role before sliding into the closer spot (Brandon League, really?).

I’ll check back in 15 or so years and see if Jansen is still dominating hitters, but for now I’ll enjoy Jansen making hitters look helpless with one pitch, just like the Greatest Reliever Ever.

Chris Moran is a second-year law student at Washington University in St. Louis. He is also an assistant coach with the baseball team at Washington University. He graduated from Wheaton College, where he wore the tools of ignorance for the baseball team. Contact him via email at chris.moran@wustl.edu or follow him on twitter @hangingslurves.